A heaping helping of Queens atmos phere with a central character who’s like Rocky Balboa fighting himself instead of Apollo Creed, “Lbs.” is a working-class hero of a film.

This low-budget indie stars an appealing Carmine Famiglietti (who also co-wrote the script) as a 27-year-old, 300-pound virgin named Neil who lives in Queens with his parents. After a heart attack costs him his job and ruins his sister’s wedding, he decides to detox from Mama’s pasta — by moving to a rusty trailer in the woods in upstate New York.

He’s joined there by his drug-addict pal, who wants to know whether male genitalia size varies with obesity (answer: Neil doesn’t know. He’s never been thin). The addict complains that the setting is too Spartan (“I got nowhere to throw up”) but Neil resolves to rough it through the winter, “Into the Wild”-style. He even means to learn how to ride a bike, because he’s a glutton for punishment. And Twinkies.

Sharply written (“Fat people, we don’t have good lingo. You guys [drug addicts] got f – – – in’ great lingo”) and woefully believable (except in an improbable bedroom scene with a cute waitress), “Lbs.” makes for an alternately sad and funny companion piece to last year’s (slightly funnier and darker) “Big Fan,” only with burritos instead of the New York Giants.